St. Elmo, Illinois Weather
Cicadas claim the scorching afternoon. Day 14 of summer. Read this microseason across nine climate regions →
St. Elmo weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 4Overcast28%—92°73°—
- SundayJul 5Heavy Drizzle24%0.09″85°73°-7°
- MondayJul 6Light Drizzle15%—86°70°+1°
- TuesdayJul 7Overcast——84°65°-2°
- WednesdayJul 8Clear12%—86°65°+2°
- ThursdayJul 9Light Drizzle38%—87°72°+1°
- FridayJul 10Light Showers38%0.37″83°70°-4°
AQI 35 (Good), driven by Ozone. AQI flat over the last 6 hours (within ±3 points). Ozone at AQI 43 now. With UV 4.7 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 27 around 1 PM.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion during the projected peak around 10 PM.
What's driving it
Ozone × UV × Sky
Ozone at AQI 43 now. With UV 4.7 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 27 around 1 PM.
- Present
- AQI 43
- UV peak
- 4.7 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 27
PM × Wind × Precip
PM2.5 at 5.8 µg/m³, PM10 at 6.1 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.95
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- background
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
If the first of July be rainy weather, 'twill rain more or less for four weeks together.
- Moonrise
- 10:49 PM
- Moonset
- 10:03 AM
- In sign
- ♓︎ Pisces
Cicadas claim the scorching afternoon
St. Elmo at a glance
- Today vs. normal: 13°F above the seasonal normal for this latitude
- Last frost: April 10 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
16-Day Forecast — St. Elmo
- Sat92°73°28%
- Sun85°73°24%
- Mon86°70°15%
- Tue84°65°9%
- Wed86°65°12%
- Thu87°72°38%
- Fri83°70°38%
- Sat86°71°25%
- Sun75°60°7%
- Mon71°58°6%
- Tue78°60°11%
- Wed81°63°13%
- Thu81°65°19%
- Fri79°71°19%
- Sat87°69°26%
- Sun87°72°19%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of July 4, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
SPC Convective Outlook
Storm Prediction Center — St. Elmo
SPC has placed St. Elmo in the Slight Risk category for severe thunderstorms today.
- TODAYSLGTSlight Risk
- TOMORROWTSTMGeneral Thunderstorms
- DAY 3TSTMGeneral Thunderstorms
Scattered severe storms possible. A few tornadoes, hail, and damaging wind gusts possible.
Source: NOAA / NWS Storm Prediction Center categorical convective outlook. Outlooks are re-issued multiple times per day; this page reflects the most recent SPC polygons covering the city’s coordinates.
ZIP codes in St. Elmo
- 62458